Mouse Spiders

Details

Mouse spiders are mygalomorph spiders of the genus Missulena, found mainly in Australia and nearby regions. They are robust, burrow-dwelling spiders with a high, glossy cephalothorax and strong fangs, somewhat resembling small tarantulas. Several species are regarded as medically important because their venom can be similar in action to that of the Australian funnel-web spiders.

Basic Biology

• Scientific scope: Genus Missulena – mouse spiders (e.g. the Eastern Mouse Spider M. bradleyi)

• Size: Body length generally about 10–35 mm, with females stockier than males.

• Longevity: Females may live for several years in their burrows, with estimates of 8–10+ years in some cases; males usually live for a shorter time.

Appearance

Mouse spiders have a bulky body, high cephalothorax and powerful chelicerae. Colour varies by species: many females are uniformly dark brown to black, whereas males may show bright patches of blue or red, such as a blue carapace or red markings on the front of the cephalothorax or abdomen. As mygalomorphs, their fangs strike downwards in a parallel motion, similar to tarantulas.

Distribution & Habitat

Most mouse spiders are endemic to mainland Australia, with some species also known from nearby regions such as New Guinea. They typically construct silk-lined burrows in the ground, sometimes with a simple or partially hinged trapdoor or a securely webbed entrance. Burrows may occur in lawns, open woodland, scrub, farmland and around gardens and roadsides.

Behaviour & Diet

Mouse spiders are primarily nocturnal ambush predators. By day they remain in the burrow, emerging to the entrance at night to seize insects and other arthropods—and occasionally small vertebrates—that pass within range. Prey is captured with a rapid lunge and subdued by a venomous bite.

Venom & Medical Significance

The venom of some mouse spider species is known to contain potent neurotoxic components and in laboratory tests can showsimilar activity to funnel-web spider venom. Documented human bites have produced a range of effects from local pain and mild systemic symptoms through to more serious neurotoxic signs in a minority of cases.

In Australia, mouse spiders are therefore treated as potentially medically significant. Modern clinical practice often uses funnel-web spider antivenom where indicated, and serious outcomes are rare when prompt medical care is available. Anyone suspected of being bitten by a mouse spider in Australia should seek urgent medical assessment.

Human Encounters & Precautions

Burrows may be located in gardens, beside paths or under objects such as stones and timber. Males wander during the mating season and are more likely to be encountered on the surface or near houses. Sensible precautions include wearing gloves when gardening, avoiding bare hands under rocks or logs, and not handling large dark spiders found in mouse spider habitat.